Pvc drain pipes sizing

[Byron malta]

Im building a new tank (170g) with a sump of 35g and will be using a 2500g/hr return pump. I m going to use the bean animal overflow. My only concern is what size plumbing should i use??? Obviously i want the primary drain to keep up with the return pump’s flow. Is there a formula to calculate this?

Your help will be greatly appreciated. Thanks

 

[AZRipp]

You really can't go too big on the drain. Go as big as your setup will allow. This will guarantee you have the flexibility for future return pump size changes and that you won't get backed up.

 

[Byron malta]

So if a 1.5 inch bulkhead fits, its better than a 1 inch. Thats what you mean i presume. Right?

 

[BornHandy]

I have a 75 gallon bean animal supplied with a neptune cor 20 (2000 gph). I tested the pump wide open, and was handling the flow with a 1.25 inch drain. I backed down to half the flow, not because of drain problems, but because of bubbles getting back to the return pump, but...

I also need to say that my 1.25 inch supply splits into two 3/4" locklines, so that undoubtedly has an impact on my flow rate.
Also, the drain was working as designed, but it was louder than I wanted (until I backed it down to half). Based off of what I saw on my tank, if you want to run that many GPH, I would do two overflows with 1.25" drains. I feel like that will be quieter than a single drain with 1.5" drains, but that is just a guess.

The only concern with doing a 1.5 inch drain is the possibility that you may not be able to get the velocity of flow in your siphon to push all of the air out. If that were to happen, the silent operation of the Bean Animal is lost. As an added precaution, you could do the secondary and emergency as a 1.5" drain, but keep the primary at 1.25. - Again, this is just me guessing based off of what I learned on my own aquarium.

 

[Byron malta]

I have a 75 gallon bean animal supplied with a neptune cor 20 (2000 gph). I tested the pump wide open, and was handling the flow with a 1.25 inch drain. I backed down to half the flow, not because of drain problems, but because of bubbles getting back to the return pump, but...

I also need to say that my 1.25 inch supply splits into two 3/4" locklines, so that undoubtedly has an impact on my flow rate.
Also, the drain was working as designed, but it was louder than I wanted (until I backed it down to half). Based off of what I saw on my tank, if you want to run that many GPH, I would do two overflows with 1.25" drains. I feel like that will be quieter than a single drain with 1.5" drains, but that is just a guess.

The only concern with doing a 1.5 inch drain is the possibility that you may not be able to get the velocity of flow in your siphon to push all of the air out. If that were to happen, the silent operation of the Bean Animal is lost. As an added precaution, you could do the secondary and emergency as a 1.5" drain, but keep the primary at 1.25. - Again, this is just me guessing based off of what I learned on my own aquarium.

It makes sense. So your primary drain is a 1.25 inch and handles 2000gph ok? If so, i could do the primary and the secondary 1.25, and make the emergency 1.5. I think i should be good

 

[BornHandy]

Let me clarify. My pump is rated for 2000, but there is certainly some loss from height, fittings, and friction. Still, it took the highest flow rate like a champ. It was just too much velocity through the overflow box and sump to be quiet. A more carefully designed (bigger) overflow box, and a few more baffles would have likely solved my problem.

 

[BornHandy]

Oh, and I see a 35 gallon sump is in the plan. It may be tough to get silent flow at that volume. I would go bigger if possible. That would give more room to baffle out bubbles and sound.

 

[Byron malta]

Oh, and I see a 35 gallon sump is in the plan. It may be tough to get silent flow at that volume. I would go bigger if possible. That would give more room to baffle out bubbles and sound.

I calculated the volume of water flowing through the sump. Sump size is 130*45*50 cm. Its not a small sump i guess

 

[BornHandy]

Oh, that's roughly 75 gallons. Should be fine!

 

[lapin]

https://flexpvc.com/Reference/WaterFlowBasedOnPipeSize.shtml

You will get a little more flow than just std gravity if your pipe goes straight down to the sump.